diff --git a/doc/buildings.png b/doc/buildings.png
new file mode 100644
index 0000000..c457d53
Binary files /dev/null and b/doc/buildings.png differ
diff --git a/readme.md b/readme.md
index 395df64..9a1ad0b 100644
--- a/readme.md
+++ b/readme.md
@@ -99,6 +99,12 @@ Some icons can be combined into new icons.
 Map elements
 ------------
 
+### 3D buildings ###
+
+Simple shapes for walls, shade, and roof.
+
+![3D buildings](doc/buildings.png)
+
 ### Trees ###
 
 Tree leaf types, leaf cycles, and genes.
diff --git a/roentgen/mapper.py b/roentgen/mapper.py
index c9ac293..e37b705 100644
--- a/roentgen/mapper.py
+++ b/roentgen/mapper.py
@@ -973,12 +973,11 @@ class Painter:
                    node.tags["natural"] == "tree" and
                    "diameter_crown" in node.tags):
                 continue
-            for i in range(8):
-                self.output_file.circle(
-                    float(node.x) + (random.random() - 0.5) * 10,
-                    float(node.y) + (random.random() - 0.5) * 10,
-                    float(node.tags["diameter_crown"]) * 1.5,
-                    color='688C44', fill='688C44', opacity=0.2)
+            self.output_file.circle(
+                float(node.x) + (random.random() - 0.5) * 10,
+                float(node.y) + (random.random() - 0.5) * 10,
+                float(node.tags["diameter_crown"]) * 1.2,
+                color='688C44', fill='688C44', opacity=0.3)
 
         # All other nodes